Nail varnish composition comprising a block polymer

ABSTRACT

The present invention relates to a nail varnish composition comprising, in a cosmetically acceptable medium comprising at least one organic solvent, at least one block polymer, the composition being capable of forming a film with a tangent delta (tgδ) dampening power of greater than or equal to 0.4 at a temperature of 30° C. and a frequency of 20 Hz. A further subject of the invention is a method for producing a glossy film comprising applying to nails such a composition, wherein a glossy film is produced and which shows good staying power and/or wear resistance.

[0001] This application claims priority under 35 U.S.C. §119 ofApplication No. 0211949, filed Sep. 26, 2002, Application No. 0216437,filed Dec. 20, 2002, and Application No. 0306121, filed May 21, 2003, inFrance, all of which are incorporated herein by reference.

[0002] The present invention relates to a nail varnish compositioncomprising at least one block polymer. The invention also relates to amakeup or care process for the nails.

[0003] Compositions to be applied, for example to the nails, such assolvent-based nail varnishes or nailcare bases, usually comprising atleast one film-forming polymer, optionally at least one plasticizer,pigments, rheological agents and solvents, are known.

[0004] At the present time, nitrocellulose is the film-forming agentmost widely used in solvent-based nail varnishes in formulations withoptimized gloss and staying power.

[0005] Formulations comprising nitrocelluloses may make it possible toobtain films with a satisfactory level of hardness and gloss, but theformulations may lack adhesion to the nail. This drawback may beovercome by adding plasticizers, but the addition of plasticizers orco-resins to such formulations generally requires that they be added invery large amounts, on the order of those of the nitrocellulose.

[0006] Furthermore, the presence of plasticizers in these formulationsmay be reflected, after formation of the film and drying, by a change inthe properties of the film over time. This may be due both to a slowevaporation of the residual solvents contained in the film after dryingand to a potential loss of some of the plasticizers, for example byevaporation, leading to hardening of the film over time and poor chipresistance of the film.

[0007] The research efforts made towards replacing nitrocellulose withother film-forming agents, such as polyacrylics and polyurethanes, innail varnishes—for instance the aqueous polyurethane dispersionsdescribed in document EP 0 648 485—have not given completelysatisfactory results, for example, in terms of staying power andresistance to external factors, such as water or detergents.

[0008] The present inventors have discovered, surprisingly, that a nailvarnish composition with a tangent delta (tgδ) dampening power ofgreater than or equal to 0.4 makes it possible to obtain at least one ofthe following properties, while at the same time producing a film ofglossy composition:

[0009] plasticization of the resulting film without needing to add largeamounts of external plasticizers, while at the same time maintaining agood level of hardness of the film, and

[0010] good impact strength and/or chip strength of the nail varnishcomposition and therefore an improvement in the staying power of thevarnishes on the nail over time and/or in their wear resistance.

[0011] Disclosed herein is a nail varnish composition comprising, in acosmetically acceptable medium comprising at least one organic solvent,at least one block polymer, the composition being capable of forming afilm with a tangent delta (tgδ) dampening power of greater than or equalto 0.4 at a temperature of 30° C. and a frequency of 20 Hz.

[0012] As defined herein, the expression “cosmetically acceptablemedium” means a non-toxic medium that may be applied to at least one ofhuman skin, integuments, and the lips of the face.

[0013] Also disclosed herein is a cosmetic non-therapeutic makeup orcare process for the nails, comprising applying to the nails one coat ofthe nail varnish composition as defined above.

[0014] Further disclosed herein is a method for producing a glossy filmcomprising applying to nails a nail varnish composition comprising atleast one block polymer, the composition being capable of forming a filmwith a tangent delta (tgδ) dampening power of greater than or equal to0.4 at a temperature of 30° C. and a frequency of 20 Hz, wherein aglossy film is produced with at least one of good staying power and goodwear resistance.

[0015] The at least one block polymer disclosed herein may be formulatedas a sole film-forming polymer or may be combined with at least onestandard film-forming polymer, for example nitrocellulose or a cellulosederivative, without having the drawback, in the case of a cellulosederivative, of adding large amounts of plasticizers.

[0016] The composition disclosed herein may be capable of forming a filmhaving viscoelastic behavior.

[0017] In general, a material may be viscoelastic when, due to theeffect of shear, it has both the characteristics of a purely elasticmaterial, i.e., it is capable of storing energy, and the characteristicsof a purely viscous material, i.e., it is capable of dissipating energy,and for which the response to stresses is a function of time(non-instantaneous response).

[0018] The film of the composition disclosed herein may be characterizedby its dampening power tgδ, which is defined as the ratio between thedissipated energy and the transmitted energy in the material.

[0019] The composition disclosed herein may be capable of forming a filmwith a dampening power tgδ of greater than or equal to 0.4, for exampleranging from 0.4 to 1.5, in an embodiment greater than or equal to 0.5,for example ranging from 0.5 to 1.5, and in another embodiment greaterthan or equal to 0.6, for example ranging from 0.6 to 1, at atemperature of 30° C. and a frequency of 20 Hz. Moreover, thecomposition disclosed herein may be capable of forming a film with astorage modulus E′ of greater than or equal to 1 MPa, for exampleranging from 1 MPa to 5000 MPa, in one embodiment greater than or equalto 5 MPa, for example ranging from 5 to 1000 MPa, and in anotherembodiment greater than or equal to 10 MPa, for example ranging from 10to 500 MPa, at a temperature of 30° C. and a frequency of 0.1 Hz.

[0020] Methods for Measuring the Characteristics of the Film Obtainedwith the Inventive Composition

[0021] The dampening power tgδ is measured by DMTA (Dynamic andMechanical Temperature Analysis).

[0022] To measure the dampening power tgδ of the film of thecomposition, viscoelasticimetry tests are performed using a DMTA machinefrom Polymer TA Instruments (model DMA2980) on a sample of film of thecomposition. The sample is prepared by pouring the composition into aTeflon-coated mold, followed by drying on a plate thermostaticallymaintained at 30° C. for 24 hours, under ambient humidity conditions(such as 50%±15% RH). Specimens are then cut from the film thus obtained(for example using a sample punch). These specimens may be about 200 μmthick, about 5 to 10 mm wide and have a working length of about 10 to 15mm, after drying for 24 hours.

[0023] The measurements are performed at a constant temperature of 30°C.

[0024] The sample is subjected to a tensile stress and small strains(for example, a sinusoidal displacement of ±8 μm is applied thereto)during frequency scanning, the frequency ranging from 0.1 to 20 Hz. Theprocess is thus performed in the linear domain, with small levels ofstrain.

[0025] From these measurements, the complex modulus E*=E′ +iE″ of thefilm of the test composition may be determined, wherein E′ is thestorage modulus and E″ is the loss modulus. From these measurements, thedampening power: tgδ=E″/E′, is also deduced.

[0026] The composition disclosed herein may be, for example, capable offorming a film having a breaking strain of greater than or equal to 5%,for example ranging from 5% to 500%, and in an embodiment greater thanor equal to 15%, for example ranging from 15% to 400%, and/or a breakingenergy per unit volume Wr of greater than or equal to 0.2 J/cm³, forexample ranging from 0.2 to 100 J/cm³, and in an embodiment greater than1 J/cm³, for example ranging from 1 to 50 J/cm³.

[0027] The breaking strain and the breaking energy per unit volume aredetermined by tensile tests performed on a film of the composition about200 μm thick. The film is obtained by pouring the composition onto aTeflon-coated mold, followed by drying on a plate thermostaticallymaintained at 30° C. for 7 days, under ambient humidity conditions (suchas 50%±15% RH). To perform these tests, the film is cut into, forexample, dumbbell-shaped specimens with a working length of 33±1 mm anda working width of 6 mm. The cross section (S) of the specimen is thendefined as: S=width×thickness (cm²); this cross section will be used tocalculate the stress.

[0028] The tests are performed, for example, on a tensile testingmachine sold under the name LLOYD® LR5K. The measurements are performedat 20° C.

[0029] The specimens are pulled at a travelling speed of 33 mm/minute,corresponding to a rate of 100% elongation per minute.

[0030] A travelling speed is thus applied and the elongation ΔL of thespecimen and the force F required to apply this elongation aresimultaneously measured. From these data ΔL and F, the stress σ andstrain ε parameters are determined.

[0031] A curve of stress σ=(F/S) as a function of the strainε=(ΔL/Lo)×100 is thus obtained. The test is conducted until the specimenbreaks, wherein Lo is the initial length of the specimen.

[0032] The breaking strain is the maximum strain of the sample beforethe breaking point (in %).

[0033] The breaking energy per unit volume (Wr) in J/cm³ is defined asthe area under this stress/strain curve such that:W_(r) = ∫₀^(??)σ ⋅ ɛ⋅  ɛ

[0034] 1) Block Polymer

[0035] The at least one block polymer of the composition disclosedherein may be, for example, a film-forming linear block ethylenepolymer.

[0036] For purposes of the invention, the term “ethylene polymer” isunderstood to mean a polymer obtained by the polymerization of monomerscontaining an ethylenically unsaturated group.

[0037] The term “block polymer” is understood to mean a polymercontaining at least two separate blocks, for example at least threeseparate blocks.

[0038] The block polymer may be a polymer with, for example, a linearstructure. In contrast, a polymer having a non-linear structure may be,for example, a polymer with a branched, star, grafted or otherstructure.

[0039] The term “film-forming polymer” is understood to mean a polymercapable of forming, by itself or in the presence of at least oneauxiliary film-forming agent, a continuous film that adheres to asupport, for example, to keratinous materials.

[0040] The at least one block polymer of the composition according tothe present invention comprises at least one first block and at leastone second block that have different glass transition temperatures (Tg).The at least one first and second blocks may be linked together via atleast one intermediate segment comprising at least one constituentmonomer of the at least one first block and at least one constituentmonomer of the at least one second block. In one embodiment, the atleast one first block and the at least one second block are incompatiblewith each other.

[0041] The expression blocks “that are incompatible with each other”means that the mixture of the polymer formed by the at least one firstblock and the polymer formed by the at least one second block(hereinafter referred to as “the polymer mixture”) is immiscible in themain polymerization organic solvent of the block copolymer at roomtemperature (25° C.) and atmospheric pressure (10⁵ Pa), at a content ofthe polymer mixture greater or equal to 5% by weight of the total weightof polymers and solvent, and wherein

[0042] (i) the polymer formed by the at least one first block and thepolymer formed by the at least one second block are present in thepolymer mixture in a ratio ranging from 10/90 to 90/10 by weight, and

[0043] (ii) each of the polymer formed by the at least one first blockand the polymer formed by the at least one second block has an averagemolar mass (weight-average or number-average molar mass) equal to theaverage mass of the block polymer +/−15%.

[0044] The expression “main polymerization organic solvent” means, inthe case where there is a mixture of polymerization solvents, thepolymerization solvent which has the highest content by weight relativeto the total weight of the organic polymerization solvents. In the casewhere there is a mixture of polymerization solvents and two or more ofthe solvents are present in identical weight ratios, the polymer mixtureis immiscible in at least one of the solvents. In the case where thepolymerization is made in a single solvent, the single solvent is themain solvent.

[0045] The at least one intermediate segment may be a block comprisingat least one constituent monomer of the at least one first block and atleast one constituent monomer of the at least one second block of thepolymer and allows these blocks to be “compatibilized.”

[0046] In one embodiment, the at least one block polymer does notcomprise any silicon atoms in its skeleton. The term “skeleton” meansthe main chain of the polymer, as opposed to the pendent side chains.

[0047] In one embodiment, the polymer disclosed herein is notwater-soluble, that is to say the polymer is not soluble in water or ina mixture of water and linear or branched lower monoalcohols having from2 to 5 carbon atoms, such as ethanol, isopropanol, or n-propanol,without pH modification, with an active material content of less than 1%by weight, at room temperature (25° C.).

[0048] In one embodiment, the at least one block polymer is not anelastomer.

[0049] The expression “non-elastomeric polymer” means a polymer which,when submitted to a stretching stress (for example when stretched by 30%of the original length) does not return to approximately its originallength when released. Specifically, “non-elastomeric polymer” means apolymer with an instantaneous recovery R_(i)<50% and a delayed recoveryR_(2h)<70% after having undergone a 30% elongation. In one embodiment,R_(i) is <30% and R_(2h) is <50%.

[0050] More specifically, the elastomeric nature of the polymer may bedetermined according to the following protocol:

[0051] A polymer film is prepared by pouring a solution of the polymerinto a Teflon-coated mold followed by drying for 7 days under ambientconditions regulated to 23±5° C. and 50±10% relative humidity. A filmabout 100 μm thick is thus obtained, from which are cut for examplerectangular specimens (for example using a punch) 15 mm wide and 80 mmlong. This sample is subjected to a tensile stress using a machine soldunder the reference Zwick, under the same temperature and humidityconditions as for the drying operation. The specimens are drawn at aspeed of 50 mm/minute and the distance between the jaws of the machineis 50 mm, which corresponds to the initial length (Lo) of the specimen.

[0052] The instantaneous recovery R_(i) is determined in the followingmanner:

[0053] The specimen is stretched by 30% (ε_(max)), i.e., about 0.3 timesits initial length (Lo). The stress is released by applying a returnspeed equal to the tensile speed, i.e., 50 mm/minute, and the residualelongation percentage of the specimen, after returning to zero stress(ε_(i)), is measured.

[0054] The percentage instantaneous recovery (R_(i)) is given by theformula below:

R_(i)=((ε_(max)−ε_(i))/ε_(max))×100

[0055] To determine the delayed recovery, the residual percentage degreeof elongation (ε_(2h)) of the specimen is measured 2 hours afterreturning to zero stress.

[0056] The delayed percentage recovery in % after 2 hours (R_(2h)) isgiven by the formula below:

R_(2h)=((ε_(max)−ε_(2h))/ε_(max))×100

[0057] For example, in one embodiment, the at least one block polymer ofthe composition disclosed herein has an instantaneous recovery R_(i) of10% and a delayed recovery R_(2h) of 30%.

[0058] The at least one block polymer disclosed herein comprises atleast one first block and at least one second block that have differentglass transition temperatures (Tg); the at least one first and secondblocks being linked together via at least one intermediate segmentcomprising at least one constituent monomer of the at least one firstblock and at least one constituent monomer of the at least one secondblock.

[0059] It is pointed out that, in the text hereinabove and hereinbelow,the terms “first” and “second” blocks do not in any way condition theorder of the blocks in the structure of the polymer.

[0060] The polydispersity index of the polymer disclosed herein may begreater than 2, for example ranging from 2 to 9, in one embodimentgreater than or equal to 2.5, for example ranging from 2.5 to 8, and inanother embodiment greater than or equal to 2.8, and for example rangingfrom 2.8 to 6.

[0061] The polydispersity index I of the polymer may be equal to theratio of the weight-average mass Mw to the number-average mass Mn.

[0062] The weight-average (Mw) and number-average (Mn) molar masses aredetermined by gel permeation liquid chromatography (THF solvent,calibration curve established with linear polystyrene standards,refractometric detector).

[0063] The weight-average mass (Mw) of the polymer disclosed herein maybe, for example, less than or equal to 300,000, for example ranging from35,000 to 200,000, and as a further example, ranging from 45,000 to150,000.

[0064] The number-average mass (Mn) of the polymer disclosed herein maybe less than or equal to 70,000, for example ranging from 10,000 to60,000, and as a further example, ranging from 12,000 to 50,000.

[0065] Each block of the at least one block polymer of the compositiondisclosed herein may be derived from one type of monomer or from severaldifferent types of monomers.

[0066] This means that each block may comprise a homopolymer or acopolymer. This copolymer constituting the block may in turn be randomor alternating.

[0067] The at least one intermediate segment comprising at least oneconstituent monomer of the at least one first block and at least oneconstituent monomer of the at least one second block of the polymer maybe a random polymer.

[0068] In an embodiment, the at least one intermediate segment may be,for example, derived from constituent monomers of the at least one firstblock and of the at least one second block. For example, the at leastone intermediate segment may be at least 85% derived from constituentmonomers of the at least one first block and of the at least one secondblock, in a further embodiment at least 90% derived, for example atleast 95%, and as a further example 100% derived.

[0069] The at least one intermediate segment of the at least one blockpolymer has a glass transition temperature Tg ranging from the glasstransition temperatures of the at least one first and second blocks.

[0070] The at least one first and second blocks of the at least oneblock polymer of the composition have different glass transitiontemperatures.

[0071] The glass transition temperatures indicated for the at least onefirst and second blocks of the at least one block polymer may betheoretical Tg values determined from the theoretical Tg values of theconstituent monomers of each of the blocks. The theoretical Tg valuesmay be found in a reference manual, such as, the Polymer Handbook, 3rdEdition, 1989, John Wiley, which is hereby incorporated by reference,according to the following relationship, known as Fox's law:${{1/{Tg}} = {\sum\limits_{i}\left( {{\overset{\_}{\omega}}_{i}/{Tg}_{i}} \right)}},$

[0072] ω_(i) being the mass fraction of the monomer i in the block underconsideration and Tg_(i) being the glass transition temperature of thehomopolymer of the monomer i.

[0073] Unless otherwise indicated, the Tg values indicated for the atleast one first and second blocks of the at least one block polymer aretheoretical Tg values.

[0074] The difference between the glass transition temperatures of theat least one first and second blocks of the at least one block polymermay be generally greater than 10° C., for example greater than 20° C.,and as a further example greater than 30° C.

[0075] In one embodiment, the at least one first block of the at leastone block polymer may be chosen from:

[0076] a) a block with a Tg of greater than or equal to 40° C.,

[0077] b) a block with a Tg of less than or equal to 20° C., and

[0078] c) a block with a Tg of between 20 and 40° C.,

[0079] and the at least one second block may be chosen from a block ofcategory a), b) or c) that is different from the at least one firstblock.

[0080] In the present invention, the expression:

[0081] “between . . . and . . . ” is intended to denote a range ofvalues for which the limits mentioned are excluded, and

[0082] “from . . . to . . . ” and “ranging from . . . to . . . ” areintended to denote a range of values for which the limits are included.

[0083] a) Block with a Tq of Greater Than or Equal to 40° C.

[0084] The block with a Tg of greater than or equal to 40° C. of the atleast one block polymer has, for example, a Tg ranging from 40 to 150°C., for example greater than or equal to 50° C., for example rangingfrom 50° C. to 120° C., and as a further example greater than or equalto 60° C., for example ranging from 60° C. to 120° C.

[0085] The block with a Tg of greater than or equal to 40° C. may be ahomopolymer or a copolymer.

[0086] In the case where this block is a homopolymer, it may be derivedfrom monomers wherein the homopolymers prepared from these monomers haveglass transition temperatures of greater than or equal to 40° C. Thisfirst block may be a homopolymer comprising one type of monomer (forwhich the Tg of the corresponding homopolymer is greater than or equalto 40° C.).

[0087] In the case where the first block is a copolymer, it may betotally or partially derived from at least one monomer, the nature andconcentration of which are chosen so that the Tg of the resultingcopolymer is greater than or equal to 40° C. The copolymer may comprise,for example:

[0088] monomers wherein the homopolymers prepared from these monomershave Tg values of greater than or equal to 40° C., for example a Tgranging from 40 to 150° C., for example greater than or equal to 50° C.,for example ranging from 50° C. to 120° C., and as a further examplegreater than or equal to 60° C., for example ranging from 60° C. to 120°C., and

[0089] monomers wherein the homopolymers prepared from these monomershave Tg values of less than 40° C., chosen from monomers with a Tg ofbetween 20 and 40° C. and/or monomers with a Tg of less than or equal to20° C., for example a Tg ranging from −100 to 20° C., in an embodimentless than 15° C., for example ranging from −80° C. to 15° C., and as afurther example less than 10° C., for example ranging from −50° C. to 0°C., as described later.

[0090] The monomers whose homopolymers have a glass transitiontemperature of greater than or equal to 40° C. are chosen, for example,from the following monomers, also known as the main monomers:

[0091] methacrylates of formula CH₂═C(CH₃)—COOR₁, wherein R₁ is chosenfrom linear and branched unsubstituted alkyl groups containing from 1 to4 carbon atoms, such as methyl, ethyl, propyl and isobutyl groups, or R₁is chosen from a C₄ to C₁₂ cycloalkyl group,

[0092] acrylates of formula CH₂═CH—COOR₂, wherein R₂ is chosen from a C₄to C₁₂ cycloalkyl group such as an isobornyl group or a tert-butylgroup,

[0093] (meth)acrylamides of formula:

[0094] wherein R₇ and R₈, which may be identical or different, arechosen from a hydrogen atom, and linear and branched C₁ to C₁₂ alkylgroups such as n-butyl, t-butyl, isopropyl, isohexyl, isooctyl andisononyl groups; or R₇ is H and R₈ is a 1,1-dimethyl-3-oxobutyl group,

[0095] and R′ is chosen from H and methyl. Examples of monomers that maybe mentioned include N-butylacrylamide, N-t-butylacrylamide,N-isopropylacrylamide, N,N-dimethylacrylamide and N,N-dibutylacrylamide,

[0096] and mixtures thereof.

[0097] Examples of main monomers are, for example, methyl methacrylate,isobutyl (meth)acrylate and isobornyl (meth)acrylate, and mixturesthereof.

[0098] b) Block with a Tq of Less Than or Equal to 20° C.

[0099] The block with a Tg of less than or equal to 20° C. of the atleast one block polymer has, for example, a Tg ranging from −100 to 20°C., in an embodiment less than or equal to 15° C., for example rangingfrom −80° C. to 15° C., and in another embodiment less than or equal to10° C., for example ranging from −50° C. to 0° C.

[0100] The block with a Tg of less than or equal to 20° C. may be ahomopolymer or a copolymer.

[0101] In the case where this block is a homopolymer, it may be derivedfrom monomers wherein the homopolymers prepared from these monomers haveglass transition temperatures of less than or equal to 20° C. Thissecond block may be a homopolymer comprising one type of monomer (forwhich the Tg of the corresponding homopolymer is less than or equal to20° C.).

[0102] In the case where the block with a Tg of less than or equal to20° C. is a copolymer, it may be totally or partially derived from atleast one monomer, the nature and concentration of which may be chosensuch that the Tg of the resulting copolymer is less than or equal to 20°C.

[0103] It may comprise, for example,

[0104] at least one monomer whose corresponding homopolymer has a Tg ofless than or equal to 20° C., for example a Tg ranging from −100° C. to20° C., in another embodiment less than 15° C., for example ranging from−80° C. to 15° C., and in another embodiment less than 10° C., forexample ranging from −50° C. to 0° C., and

[0105] at least one monomer whose corresponding homopolymer has a Tg ofgreater than 20° C., such as monomers with a Tg of greater than or equalto 40° C., for example a Tg ranging from 40 to 150° C., in anotherembodiment greater than or equal to 50° C., for example ranging from 50°C. to 120° C., and in another example greater than or equal to 60° C.,for example ranging from 60° C. to 120° C., and/or monomers with a Tg ofbetween 20 and 40° C., as described above.

[0106] In one embodiment, the block with a Tg of less than or equal to20° C. is a homopolymer.

[0107] The monomers whose homopolymer has a Tg of less than or equal to20° C. may be, for example, chosen from the following monomers, or mainmonomer:

[0108] acrylates of formula CH₂═CHCOOR₃, wherein R₃ is chosen fromlinear and branched C₁ to C₁₂ unsubstituted alkyl groups, with theexception of the tert-butyl group, wherein at least one heteroatomchosen from O, N and S is (are) optionally intercalated,

[0109] methacrylates of formula CH₂═C(CH₃)—COOR₄, wherein R₄ is chosenfrom linear and branched C₆ to C₁₂ unsubstituted alkyl groups, whereinat least one heteroatom chosen from O, N and S is (are) optionallyintercalated,

[0110] vinyl esters of formula R₅—CO—O—CH═CH₂, wherein R₅ is chosen fromlinear and branched C₄ to C₁₂ alkyl groups,

[0111] C₄ to C₁₂ alcohol and vinyl alcohol ethers,

[0112] N—(C₄ to C₁₂)alkyl acrylamides, such as N-octylacrylamide,

[0113] and mixtures thereof.

[0114] Examples of main monomers for the block with a Tg of less than orequal to 20° C. include, for example, alkyl acrylates whose alkyl chaincontains from 1 to 10 carbon atoms, with the exception of the tert-butylgroup, such as methyl acrylate, isobutyl acrylate and 2-ethylhexylacrylate, and mixtures thereof.

[0115] c) Block with a Tq of Between 20 and 40° C.

[0116] The block with a Tg of between 20 and 40° C. of the at least oneblock polymer may be a homopolymer or a copolymer.

[0117] In the case where this block is a homopolymer, it may be derivedfrom monomers (or main monomer) wherein the homopolymers prepared fromthese monomers have glass transition temperatures of between 20 and 40°C. This first block may be a homopolymer, comprising one type of monomer(for which the Tg of the corresponding homopolymer is between 20° C. to40° C.).

[0118] The monomers whose homopolymer has a glass transition temperatureof between 20 and 40° C. may be, for example, chosen from n-butylmethacrylate, cyclodecyl acrylate, neopentyl acrylate andisodecylacrylamide, and mixtures thereof.

[0119] In the case where the block with a Tg of between 20 and 40° C. isa copolymer, it may be totally or partially derived from at least onemonomer (or main monomer) whose nature and concentration are chosen sothat the Tg of the resulting copolymer is between 20 and 40° C.

[0120] The block with a Tg of between 20 and 40° C. may be a copolymertotally or partially derived from:

[0121] main monomers whose corresponding homopolymer has a Tg of greaterthan or equal to 40° C., for example a Tg ranging from 40° C. to 150°C., in an embodiment greater than or equal to 50° C., for exampleranging from 50 to 120° C., and in another embodiment greater than orequal to 60° C., for example ranging from 60° C. to 120° C., asdescribed above, and/or

[0122] main monomers whose corresponding homopolymer has a Tg of lessthan or equal to 20° C., for example a Tg ranging from −100 to 20° C.,in another embodiment less than or equal to 15° C., for example rangingfrom −80° C. to 15° C., and in another embodiment less than or equal to10° C., for example ranging from −50° C. to 0° C., as described above.

[0123] The monomers may be chosen so that the Tg of the copolymerforming the first block is between 20 and 40° C.

[0124] Such main monomers may be chosen, for example, from methylmethacrylate, isobornyl acrylate and methacrylate, butyl acrylate and2-ethylhexyl acrylate, and mixtures thereof.

[0125] In one embodiment, the proportion of the second block with a Tgof less than or equal to 20° C. ranges from 10% to 85% by weight, forexample from 20% to 70%, and as a further example from 20% to 50% byweight of the polymer.

[0126] However, each of the blocks of the at least one block polymer maycontain in small proportion at least one constituent monomer of theother block.

[0127] Thus, the at least one first block of the at least one blockpolymer may contain at least one constituent monomer of the at least onesecond block, and vice versa.

[0128] Each of the at least one first and/or second blocks of the atleast one block polymer may comprise, in addition to the monomersindicated above, at least one other monomer known as additionalmonomers, which are different from the main monomers mentioned above.

[0129] The nature and amount of this or these additional monomer(s) maybe chosen such that the block in which they are present has the desiredglass transition temperature.

[0130] This additional monomer may be chosen, for example, from:

[0131] a) hydrophilic monomers such as:

[0132] ethylenically unsaturated monomers comprising at least onecarboxylic or sulphonic acid function, for example, acrylic acid,methacrylic acid, crotonic acid, maleic anhydride, itaconic acid,fumaric acid, maleic acid, acrylamidopropanesulphonic acid, vinylbenzoicacid, vinylphosphoric acid, and salts thereof,

[0133] ethylenically unsaturated monomers comprising at least onetertiary amine function, for instance 2-vinylpyridine, 4-vinylpyridine,dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate anddimethylaminopropylmethacrylamide, and salts thereof,

[0134] methacrylates of formula CH₂═C(CH₃)—COOR₆, wherein R₆ is chosenfrom linear and branched alkyl groups containing from 1 to 4 carbonatoms, such as methyl, ethyl, propyl and isobutyl groups, the alkylgroup being substituted with at least one substituent chosen fromhydroxyl groups (for instance 2-hydroxypropyl methacrylate and2-hydroxyethyl methacrylate) and halogen atoms (Cl, Br, I or F), such astrifluoroethyl methacrylate,

[0135] methacrylates of formula CH₂═C(CH₃)—COOR₉, wherein R₉ is chosenfrom linear and branched C₆ to C₁₂ alkyl groups wherein at least oneheteroatom chosen from O, N and S is (are) optionally intercalated,wherein the alkyl group is substituted with at least one substituentchosen from hydroxyl groups and halogen atoms (Cl, Br, I or F);

[0136] acrylates of formula CH₂═CHCOOR₁₀, wherein R₁₀ may be chosen fromlinear and branched C₁ to C₁₂ alkyl groups substituted with at least onesubstituent chosen from hydroxyl and halogen atoms (Cl, Br, I or F),such as 2-hydroxypropyl acrylate and 2-hydroxyethyl acrylate;(C₁-C₁₋₂)alkyl-O-POE (polyoxyethylene) with repetition of theoxyethylene unit 5 to 30 times, for example methoxy-POE; and apolyoxyethylenated group comprising from 5 to 30 ethylene oxide units

[0137] b) ethylenically unsaturated monomers comprising at least onesilicon atom, such as methacryloxypropyltrimethoxysilane andmethacryloxypropyl-tris(trimethylsiloxy)silane,

[0138] and mixtures thereof.

[0139] Examples of additional monomers include acrylic acid, methacrylicacid, trifluoroethyl methacrylate, and mixtures thereof.

[0140] According to an embodiment, the at least one block polymer of thecomposition disclosed herein may be a non-silicone polymer, i.e., apolymer free of silicon atoms.

[0141] This or these additional monomer(s) generally represent(s) anamount of less than or equal to 30% by weight, for example from 1% to30% by weight, as a further example from 5% to 20% by weight and asanother example from 7% to 15% by weight, relative to the total weightof the first and/or second blocks.

[0142] In one embodiment, each of the at least one first and secondblocks of the at least one block polymer comprises at least one monomerchosen from acrylic acid, acrylic acid esters, methacrylic acid,methacrylic acid esters, and mixtures thereof.

[0143] In one embodiment, each of the at least one first and secondblocks of the at least one block polymer may be totally derived from atleast one monomer chosen from acrylic acid, acrylic acid esters,methacrylic acid, and methacrylic acid esters.

[0144] In one embodiment, the block polymer disclosed herein is free ofstyrene. “Polymer free of styrene” means that the polymer contains lessthan 10% by weight, relative to the total weight of the polymer, forexample, less than 5% by weight, as a further example less than 2% byweight and as another example less than 1% by weight, or does notcontain at all any styrene monomer including styrene and styrenederivatives such as for instance methylstyrene, chlorostyrene orchloromethylstyrene.

[0145] The at least one block polymer of the composition disclosedherein may be obtained by free-radical solution polymerization accordingto the following preparation process:

[0146] a portion of the polymerization solvent is introduced into asuitable reactor and heated until an adequate temperature for thepolymerization is reached (typically ranging from 60 to 120° C.),

[0147] once this temperature is reached, the at least one constituentmonomer of the at least one first block is introduced in the presence ofsome of the polymerization initiator,

[0148] after a time T corresponding to a maximum degree of conversion of90%, the at least one constituent monomer of the at least one secondblock and the rest of the initiator are introduced,

[0149] the mixture is left to react for a time T′ (ranging from 3 to 6hours), after which the mixture is cooled to room temperature (25° C.),

[0150] the polymer dissolved in the polymerization solvent is obtained.

[0151] The term “polymerization solvent” means a solvent or a mixture ofsolvents. The polymerization solvent may be chosen, for example, fromethyl acetate, butyl acetate, alcohols such as isopropanol or ethanol,aliphatic alkanes such as isododecane, and mixtures thereof. In oneembodiment, the polymerization solvent is a mixture of butyl acetate andisopropanol or isododecane.

[0152] First Embodiment

[0153] According to a first embodiment, the at least one block polymerof the composition disclosed herein comprises at least one (for example,one) first block with a Tg of greater than or equal to 40° C., asdescribed above in a), and at least one (for example, one) second blockwith a Tg of less than or equal to 20° C., as described above in b).

[0154] The first block with a Tg of greater than or equal to 40° C. ofthe at least one block polymer may be a copolymer derived from monomerswherein the homopolymer prepared from these monomers has a glasstransition temperature of greater than or equal to 40° C., such as themonomers described above.

[0155] The second block with a Tg of less than or equal to 20° C. may bea homopolymer derived from monomers wherein the homopolymer preparedfrom these monomers has a glass transition temperature of less than orequal to 20° C., such as the monomers described above.

[0156] The proportion of the block with a Tg of greater than or equal to40° C. of the at least one block polymer ranges from 20% to 90%, forexample from 30% to 80%, and as a further example from 50% to 70% byweight of the polymer. In one embodiment, the proportion of the blockwith a Tg of less than or equal to 20° C. ranges from 5% to 75%, forexample from 15% to 50%, and as a further example from 25% to 45% byweight of the polymer.

[0157] Thus, according to a first variant, the at least one blockpolymer of the composition disclosed herein may comprise:

[0158] at least one first block with a Tg of greater than or equal to40° C., for example having a Tg ranging from 70 to 110° C., which is amethyl methacrylate/acrylic acid copolymer,

[0159] at least one second block with a Tg of less than or equal to 20°C., for example ranging from 0 to 20° C., which is a methyl acrylatehomopolymer, and

[0160] at least one intermediate segment which is a methylmethacrylate/acrylic acid/methyl acrylate copolymer.

[0161] According to a second variant, the at least one block polymer ofthe composition disclosed herein may comprise:

[0162] at least one first block with a Tg of greater than or equal to40° C., for example ranging from 70 to 100° C., which is a methylmethacrylate/acrylic acid/trifluoroethyl methacrylate copolymer,

[0163] at least one second block with a Tg of less than or equal to 20°C., for example ranging from 0 to 20° C., which is a methyl acrylatehomopolymer, and

[0164] at least one intermediate segment which is a methylmethacrylate/acrylic acid/methyl acrylate/trifluoroethyl methacrylaterandom copolymer.

[0165] Second Embodiment

[0166] According to a second embodiment, the at least one block polymerof the composition disclosed herein comprises at least one first blockhaving a glass transition temperature (Tg) of between 20 and 40° C., inaccordance with the blocks described in c), and at least one secondblock having a glass transition temperature of less than or equal to 20°C., as described above in b), or a glass transition temperature ofgreater than or equal to 40° C., as described in a) above.

[0167] The proportion of the at least one first block with a Tg ofbetween 20 and 40° C. ranges from 10% to 85% by weight of the polymer,for example from 30% to 80%, and as a further example from 50% to 70%.

[0168] When the at least one second block is a block with a Tg ofgreater than or equal to 40° C., it may be, for example, present in anamount ranging from 10% to 85% by weight, for example from 20% to 70%,and as a further example from 30% to 70% by weight of the polymer.

[0169] When the at least one second block is a block with a Tg of lessthan or equal to 20° C., it may be, for example, present in an amountranging from 10% to 85% by weight, for example from 20% to 70%, and as afurther example from 20% to 50% by weight of the polymer.

[0170] The at least one first block with a Tg of between 20 and 40° C.of the at least one block polymer may be a copolymer derived frommonomers wherein the corresponding homopolymer has a Tg of greater thanor equal to 40° C., and from monomers wherein the correspondinghomopolymer has a Tg of less than or equal to 20° C.

[0171] The at least one second block with a Tg of less than or equal to20° C. or with a Tg of greater than or equal to 40° C. may be ahomopolymer.

[0172] The at least one block polymer of the composition disclosedherein comprises:

[0173] at least one first block with a Tg of between 20 and 40° C., forexample with a Tg of 25 to 39° C., which may be a copolymer comprisingat least one methyl acrylate monomer, at least one methyl methacrylatemonomer and at least one acrylic acid monomer,

[0174] at least one second block with a Tg of greater than or equal to40° C., for example ranging from 85 to 125° C., which may be ahomopolymer composed of methyl methacrylate monomers, and

[0175] at least one intermediate segment comprising at least one methylacrylate, methyl methacrylate monomer, and

[0176] at least one intermediate segment comprising methyl methacrylate,at least one acrylic acid monomer, and at least one methyl acrylatemonomer.

[0177] The composition disclosed herein, for example, comprises from0.1% to 60% by weight, for example from 0.5% to 50% by weight, and as afurther example from 1% to 40% by weight, of the at least one blockpolymer relative to the total weight of the composition.

[0178] Solvent Medium

[0179] The cosmetic composition disclosed herein comprises an organicsolvent medium comprising at least one organic solvent.

[0180] The at least one organic solvent may be chosen from:

[0181] ketones that are liquid at room temperature, such as methyl ethylketone, methyl isobutyl ketone, diisobutyl ketone, isophorone,cyclohexanone, or acetone;

[0182] alcohols that are liquid at room temperature, such as ethanol,isopropanol, diacetone alcohol, 2-butoxyethanol, or cyclohexanol;

[0183] glycols that are liquid at room temperature, such as ethyleneglycol, propylene glycol, pentylene glycol, or glycerol;

[0184] propylene glycol ethers that are liquid at room temperature suchas propylene glycol monomethyl ether, propylene glycol monomethyl etheracetate, or dipropylene glycol mono-n-butyl ether;

[0185] cyclic ethers such as γ-butyrolactone;

[0186] short-chain esters (containing from 3 to 8 carbon atoms in total)such as ethyl acetate, methyl acetate, propyl acetate, isopropylacetate, n-butyl acetate, isopentyl acetate, methoxypropyl acetate, orbutyl lactate;

[0187] ethers that are liquid at room temperature, such as diethylether, dimethyl ether, or dichlorodiethyl ether;

[0188] alkanes that are liquid at room temperature, such as decane,heptane, dodecane, or cyclohexane;

[0189] alkyl sulphoxides, such as dimethyl sulphoxide;

[0190] aldehydes that are liquid at room temperature, such asbenzaldehyde or acetaldehyde;

[0191] heterocyclic compounds such as tetrahydrofuran;

[0192] propylene carbonate or ethyl 3-ethoxypropionate; and

[0193] mixtures thereof.

[0194] The solvent may be, for example, chosen from short-chain esterscontaining from 3 to 8 carbon atoms in total, such as ethyl acetate,methyl acetate, propyl acetate, isopropyl acetate, n-butyl acetate,isopentyl acetate, methoxypropyl acetate, or butyl lactate, and mixturesthereof.

[0195] The organic solvent medium, for example, has a polarity P rangingfrom 0.422 to 0.725.

[0196] The polarity is defined as a function of the solubilityparameters according to the Hansen solubility space, according to thefollowing relationship:

P={square root}(δp ² +δh ²)/δt

[0197] δh defines the specific forces of interaction (such as hydrogenbonding, acid/base bonding, donor/acceptor bonding, etc.);

[0198] δp defines the Debye interaction forces between permanent dipolesand also the Keesom interaction forces between induced dipoles andpermanent dipoles; and

[0199] δt={square root}(δp²+δh²+δd²), δd defines the London dispersionforces derived from the formation of induced dipoles during molecularimpacts.

[0200] The definition and calculation of the solubility parameters inthe Hansen three-dimensional solubility space are described in thearticle by C. M. Hansen, “The three dimensional solubility parameters,”J. Paint Technol., 39, 105 (1967), which is hereby incorporated byreference.

[0201] When the solvent medium comprises a mixture of solvents, thepolarity may be determined from the solubility parameters of themixture, which are themselves determined from those of the compoundstaken separately, according to the following relationships:

δdmixt=Σxiδdi; δpmixt=Σxiδpi and δhmixt=Σxiδhi

[0202] i i i

[0203] wherein xi is the volume fraction of the compound i in themixture.

[0204] As organic solvents with a polarity ranging from 0.422 to 0.725,mention may be made, for example, of methyl acetate, ethyl acetate,isopropyl acetate, methoxypropyl acetate, butyl lactate, acetone, methylethyl ketone, diacetone alcohol, γ-butyrolactone, tetrahydrofuran,propylene carbonate, ethyl 3-ethoxypropionate and dimethyl sulphoxide,and mixtures thereof.

[0205] The organic solvent medium may represent from 10% to 95% byweight, for example from 15% to 80% by weight, and as a further examplefrom 20% to 60% by weight, relative to the total weight of thecomposition.

[0206] Alternatively, the composition disclosed herein may, in oneembodiment, comprise an aqueous medium.

[0207] Additional Film-Forming Polymer

[0208] The composition may comprise, besides the at least one blockpolymer of the composition disclosed herein, at least one additionalpolymer, for example, a film-forming polymer. According to the presentinvention, the term “film-forming polymer” means a polymer that iscapable, by itself or in the presence of at least one auxiliaryfilm-forming agent, of forming a continuous film that adheres to asupport, for example to keratin materials.

[0209] Among the film-forming polymers that may be used in thecomposition of the present invention, mention may be made of syntheticpolymers, of free-radical type or of polycondensate type, and polymersof natural origin, and mixtures thereof.

[0210] The film-forming polymer may be chosen, for example, fromcellulose-based polymers such as nitrocellulose, cellulose acetate,cellulose acetobutyrate, cellulose acetopropionate or ethylcellulose, oralternatively polyurethanes, acrylic polymers, vinyl polymers,polyvinylbutyrals, alkyd resins, resins derived from aldehydecondensation products such as arylsulphonamide-formaldehyde resins, forinstance toluenesulphonamide-formaldehyde resin, andarylsulphonamide-epoxy resins.

[0211] Film-forming polymers that may be, for example, used includenitrocellulose RS ⅛ sec.; RS ¼ sec.; ½ sec.; RS 5 sec.; RS 15 sec.; RS35 sec.; RS 75 sec.; RS 150 sec.; AS ¼ sec.; AS ½ sec.; SS ¼ sec.; SS ½sec.; SS 5 sec., sold by the company Hercules; thetoluenesulphonamide-formaldehyde resins “KETJENTFLEX MS80” from thecompany Akzo or “SANTOLITE MHP” or “SANTOLITE MS 80” from the companyFaconnier or “RESIMPOL 80” from the company Pan Americana, the alkydresin “BECKOSOL ODE 230-70-E” from the company Dainippon, the acrylicresin “ACRYLOID B66” from the company Rohm & Haas, and the polyurethaneresin “TRIXENE PR 4127” from the company Baxenden.

[0212] The at least one additional film-forming polymer may be presentin the composition disclosed herein in an amount ranging from 0.1% to60% by weight, for example ranging from 2% to 40% by weight, and as afurther example from 5% to 25% by weight, relative to the total weightof the composition.

[0213] Plasticizer

[0214] The composition may also comprise at least one plasticizer. Inparticular, mention may be made, alone or as a mixture, of the usualplasticizers, such as:

[0215] glycols and derivatives thereof chosen from diethylene glycolethyl ether, diethylene glycol methyl ether, diethylene glycol butylether or diethylene glycol hexyl ether, ethylene glycol ethyl ether,ethylene glycol butyl ether, and ethylene glycol hexyl ether;

[0216] glycerol esters,

[0217] propylene glycol derivatives and for example propylene glycolphenyl ether, propylene glycol diacetate, dipropylene glycol butylether, tripropylene glycol butyl ether, propylene glycol methyl ether,dipropylene glycol ethyl ether, tripropylene glycol methyl ether,diethylene glycol methyl ether and propylene glycol butyl ether,

[0218] acid esters, for example carboxylic acid esters, chosen fromcitrates, phthalates, adipates, carbonates, tartrates, phosphates, andsebacates,

[0219] oxyethylenated derivatives chosen from oxyethylenated oils, forexample, plant oils chosen from castor oil; and

[0220] mixtures thereof.

[0221] The amount of plasticizer may be chosen by a person skilled inthe art on the basis of his general knowledge, so as to obtain acomposition with cosmetically acceptable properties. The plasticizer maybe, for example, present in an amount of less than 20%, for example lessthan 15%, as a further example less than 10%, and as an additionalexample less than 5% by weight relative to the total weight of thecomposition. In one embodiment, the composition disclosed herein is freeof plasticizer.

[0222] Dyestuff

[0223] The composition disclosed herein may also comprise at least onedyestuff chosen from water-soluble dyes and pulverulent dyestuffs, forinstance pigments, nacres and flakes that are well known to thoseskilled in the art. The dyestuffs may be present in the composition inan amount ranging from 0.01% to 50% by weight and for example from 0.01%to 30% by weight relative to the weight of the composition.

[0224] The term “pigments” should be understood as meaning white orcolored, mineral or organic particles of any shape, which are insolublein the physiological medium and which are intended to color thecomposition.

[0225] The term “nacres” should be understood as meaning iridescentparticles of any shape, produced for example by certain molluscs intheir shell, or alternatively synthesized.

[0226] The pigments may be white or colored, and mineral and/or organic.Among the mineral pigments that may be mentioned are titanium dioxide,optionally surface-treated, zirconium oxide or cerium oxide, and alsozinc oxide, iron oxide (black, yellow or red) or chromium oxide,manganese violet, ultramarine blue, chromium hydrate and ferric blue,and metal powders, for instance aluminium powder or copper powder. Amongthe organic pigments that may be mentioned are carbon black, pigments ofD & C type, and lakes based on cochineal carmine or on barium,strontium, calcium or aluminium.

[0227] The nacreous pigments may be chosen from white nacreous pigmentssuch as mica coated with titanium or with bismuth oxychloride, colourednacreous pigments such as titanium mica coated with iron oxides,titanium mica coated for example with ferric blue or chromium oxide,titanium mica coated with an organic pigment of the above-mentioned typeand also nacreous pigments based on bismuth oxychloride.

[0228] The water-soluble dyes are, for example, beetroot juice ormethylene blue.

[0229] The composition disclosed herein may also comprise at least onefiller, for example in an amount ranging from 0.01% to 50% by weight andfor example ranging from 0.01% to 30% by weight, relative to the totalweight of the composition. The term “filler” should be understood asmeaning colorless or white, mineral or synthetic particles of any shape,which are insoluble in the medium of the composition, irrespective ofthe temperature at which the composition is manufactured. These fillersserve for example to modify the rheology or the texture of thecomposition.

[0230] The at least one filler may be mineral or organic in any form,platelet-shaped, spherical or oblong, irrespective of thecrystallographic form (for example leaflet, cubic, hexagonal,orthorhombic, etc.). Mention may be made of talc, mica, silica, kaolin,polyamide (NYLON®) powders (ORGASOL® from Atochem), poly-β-alaninepowder and polyethylene powder, powders of polytetrafluoroethylenepolymers (TEFLON®), lauroyllysine, starch, boron nitride, hollow polymermicrospheres such as those of polyvinylidene chloride/acrylonitrile, forinstance EXAPANCEL® (Nobel Industrie) or acrylic acid copolymers(POLYTRAP® from the company Dow Corning) and silicone resin microbeads(for example TOSPEARLS® from Toshiba), elastomeric polyorganosiloxaneparticles, precipitated calcium carbonate, magnesium carbonate,magnesium hydrocarbonate, hydroxyapatite, hollow silica microspheres(SILICA BEADS® from Maprecos), glass or ceramic microcapsules, and metalsoaps derived from organic carboxylic acids containing from 8 to 22carbon atoms and for example from 12 to 18 carbon atoms, for examplezinc, magnesium or lithium stearate, zinc laurate or magnesiummyristate.

[0231] Other Additives

[0232] The composition may also comprise other ingredients commonly usedin cosmetic compositions. Such ingredients may be chosen from spreadingagents, wetting agents, dispersants, antifoams, preserving agents,UV-screening agents, active agents, surfactants, moisturizers,fragrances, neutralizers, stabilizers, and antioxidants.

[0233] Needless to say, a person skilled in the art will take care toselect this or these optional additional compound(s), and/or the amountthereof, such that the advantageous properties of the compositiondisclosed herein are not, or are not substantially, adversely affectedby the envisaged addition.

[0234] The examples that follow illustrate the invention, in anon-limiting manner.

[0235] In the examples that follow, the Tg values indicated for the atleast one first and second blocks are theoretical Tg values calculatedin the manner defined above.

EXAMPLE 1 Preparation of a poly(methyl methacrylate)/acrylic acid/methylAcrylate) Polymer

[0236] 100 g of butyl acetate were introduced into a 1 liter reactor andthe temperature was then raised so as to pass from room temperature (25°C.) to 90° C. in 1 hour. 180 g of methyl methacrylate, 30 g of acrylicacid, 40 g of butyl acetate, 70 g of isopropanol and 1.8 g of2,5-bis(2-ethylhexanoylperoxy)-2,5-dimethylhexane (TRIGONOX® 141 fromAkzo Nobel) were then added, at 90° C. and over 1 hour.

[0237] The mixture was maintained at 90° C. for 1 hour.

[0238] 90 g of methyl acrylate, 70 g of butyl acetate, 20 g ofisopropanol and 1.2 g of2,5-bis(2-ethylhexanoylperoxy)-2,5-dimethylhexane were then introducedinto the above mixture, still at 90° C. and over 1 hour.

[0239] The mixture was maintained at 90° C. for 3 hours and then dilutedwith 105 g of butyl acetate and 45 g of isopropanol, and the mixture wasthen cooled.

[0240] A solution containing 40% polymer active material in a butylacetate/isopropanol mixture was obtained.

[0241] A polymer comprising a poly(methyl methacrylate/acrylic acid)first block with a Tg of 100° C., a polymethyl acrylate second blockwith a Tg of 10° C. and an intermediate segment which was a methylmethacrylate/acrylic acid/polymethyl acrylate random polymer wasobtained.

[0242] This polymer had a weight-average mass of 52,000 and anumber-average mass of 18,000, i.e., a polydispersity index I of 2.89.

[0243] It had a storage modulus E′ equal to 90 MPa at 30° C. and 0.1 Hzand a tgδ value of 0.33 at 30° C. and 20 Hz.

EXAMPLE 2 Preparation of a poly(methyl methacrylate)/acrylic acid/methylAcrylate) Polymer

[0244] 100 g of butyl acetate were introduced into a 1 liter reactor andthe temperature was then raised so as to pass from room temperature (25°C.) to 90° C. in 1 hour. 150 g of methyl methacrylate, 30 g of acrylicacid, 30 g of methyl acrylate, 40 g of butyl acetate, 70 g ofisopropanol and 1.8 g of2,5-bis(2-ethylhexanoylperoxy)-2,5-dimethylhexane (TRIGONOX® 141 fromAkzo Nobel) were then added, at 90° C. and over 1 hour.

[0245] The mixture was maintained at 90° C. for 1 hour.

[0246] 90 g of methyl acrylate, 70 g of butyl acetate, 20 g ofisopropanol and 1.2 g of2,5-bis(2-ethylhexanoylperoxy)-2,5-dimethylhexane were then introducedinto the above mixture, still at 90° C. and over 1 hour.

[0247] The mixture was maintained at 90° C. for 3 hours and then dilutedwith 105 g of butyl acetate and 45 g of isopropanol, and the mixture wasthen cooled.

[0248] A solution containing 40% polymer active material in a butylacetate/isopropanol mixture was obtained.

[0249] A polymer comprising a poly(acrylic acid/methyl acrylate) firstblock with a Tg of 80° C., a polymethyl acrylate second block with a Tgof 10° C. and an intermediate segment which was an acrylic acid/methylacrylate/polymethyl acrylate random polymer was obtained.

[0250] This polymer had a weight-average mass of 50,000 and anumber-average mass of 17,000, i.e., a polydispersity index I of 2.95.

[0251] It had a storage modulus E′ equal to 12 MPa at 30° C. and 0.1 Hzand a tgδ value of 0.54 at 30° C. and 20 Hz.

EXAMPLE 3 Preparation of a Poly(acrylic Acid/methyl Acrylate/methylAcrylate/trifluoroethyl Methacrylate) Polymer

[0252] 100 g of butyl acetate were introduced into a 1 litre reactor andthe temperature was then raised so as to pass from room temperature (25°C.) to 90° C. in 1 hour. 120 g of methyl methacrylate, 30 g of acrylicacid, 60 g of trifluoroethyl methacrylate, 40 g of butyl acetate, 70 gof isopropanol and 1.8 g of2,5-bis(2-ethyl-hexanoylperoxy)-2,5-dimethylhexane (TRIGONOX® 141 fromAkzo Nobel) were then added, at 90° C. and over 1 hour.

[0253] The mixture was maintained at 90° C. for 1 hour.

[0254] 90 g of methyl acrylate, 70 g of butyl acetate, 20 g ofisopropanol and 1.2 g of2,5-bis(2-ethylhexanoylperoxy)-2,5-dimethylhexane were then introducedinto the above mixture, still at 90° C. and over 1 hour.

[0255] The mixture was maintained at 90° C. for 3 hours and then dilutedwith 105 g of butyl acetate and 45 g of isopropanol, and the mixture wasthen cooled.

[0256] A solution containing 40% polymer active material in a butylacetate/isopropanol mixture was obtained.

[0257] A polymer comprising a poly(acrylic acid/methylmethacrylate/trifluoroethyl methacrylate) first block with a Tg of 85°C., a polymethyl acrylate second block with a Tg of 10° C. and anintermediate segment which was an acrylic acid/methylacrylate/polymethyl acrylate/trifluoroethyl methacrylate random polymerwas obtained.

[0258] This polymer had a weight-average mass of 53,000 and anumber-average mass of 17500, i.e., a polydispersity index I of 3.03.

[0259] It had a storage modulus E′ equal to 3 MPa at 30° C. and 0.1 Hzand a tgδ value of 0.34 at 30° C. and 20 Hz.

EXAMPLE 4 Preparation of a Poly(Methyl Methacrylate/methylAcrylate/acrylic Acid) Polymer

[0260] 210 g of ethyl acetate were introduced into a 1 litre reactor andthe temperature was then increased so as to pass from room temperature(25° C.) to 78° C. over 1 hour. 54 g of methyl methacrylate, 21 g ofacrylic acid, 135 g of methyl acrylate and 1.8 g of2,5-bis(2-ethylhexanoylperoxy)-2,5-dimethylhexane (TRIGONOX® 141 fromAkzo Nobel) were then added, at 78° C. and over 1 hour.

[0261] The mixture was maintained at 90° C. for 1 hour.

[0262] 90 g of methyl methacrylate, 90 g of ethyl acetate and 1.2 g of2,5-bis(2-ethylhexanoylperoxy)-2,5-dimethylhexane were then introducedinto the above mixture, still at 78° C. and over 1 hour.

[0263] The mixture was maintained at 78° C. for 3 hours and was thendiluted with 150 g of ethyl acetate and cooled.

[0264] A solution containing 40% polymer active material in ethylacetate was obtained.

[0265] The polymer obtained comprises a poly(methyl acrylate/methylmethacrylate/acrylic acid) first block with a Tg of 35° C., apoly(methyl methacrylate) second block with a Tg of 100° C. and anintermediate segment which was a methyl methacrylate/acrylicacid/polymethyl acrylate random polymer.

[0266] This polymer had a weight-average mass of 141,000 and anumber-average mass of 50,000, i.e., a polydispersity index I of 2.82.

EXAMPLE 5 Preparation of a Poly(Methyl Methacrylate/methylAcrylate/acrylic Acid) Polymer

[0267] 100 g of butyl acetate were introduced into a 1 litre reactor andthe temperature was then raised so as to pass from room temperature (25°C.) to 90° C. over 1 hour. 50.4 g of methyl methacrylate, 21 g ofacrylic acid, 138.6 g of methyl acrylate, 40 g of butyl acetate, 70 g ofisopropanol and 1.8 g of2,5-bis(2-ethylhexanoylperoxy)-2,5-dimethylhexane (TRIGONOX® 141 fromAkzo Nobel) were then added, at 90° C. and over 1 hour.

[0268] The mixture was maintained at 90° C. for 1 hour.

[0269] 90 g of methyl methacrylate, 70 g of butyl acetate, 20 g ofisopropanol and 1.2 g of2,5-bis(2-ethylhexanoylperoxy)-2,5-dimethylhexane were then introducedinto the above mixture, still at 90° C. and over 1 hour.

[0270] The mixture was maintained at 90° C. for 3 hours and then dilutedwith 105 g of butyl acetate and 45 g of isopropanol, and cooled.

[0271] A solution containing 40% polymer active material in a butylacetate/isopropanol mixture was obtained.

[0272] The polymer obtained comprises a poly(methyl acrylate/methylmethacrylate/acrylic acid) first block with a Tg of 35° C., apoly(methyl methacrylate) second block with a Tg of 100° C. and anintermediate segment which was a methyl methacrylate/acrylicacid/polymethyl acrylate random polymer.

EXAMPLE 6 Nail Varnish

[0273] A nail varnish having the composition below was prepared: Polymerof Example 1 23.8 g AM Butyl acetate 24.99 g Isopropanol 10.71 gHexyleneglycol 2.5 g DC Red 7 Lake 1 g Hectorite modified withstearyldimethylbenzylammonium 1.3 g chloride (BENTONE ® 27V fromElementis) Ethyl acetate qs 100 g

[0274] After application to the nails, this varnish was considered ashaving very good staying power and impact strength properties.

EXAMPLE 7 Nail Varnish

[0275] A nail varnish having the composition below may be prepared:Polymer of Example 4 23.8 g AM Butyl acetate 24.99 g Isopropanol 10.71 gDC Red 7 Lake 1 g Hectorite modified with 1.3 gstearyldimethylbenzylammonium chloride (BENTONE ® 27V from Elementis)Ethyl acetate qs 100 g

[0276] Packaging:

[0277] According to another aspect of the invention, there is provided anail varnish product comprising: i) a container delimiting at least onecompartment closed by a cap, and ii) a composition according to theinvention received inside the compartment.

[0278] The container may be in the form of a bottle and can be formed,at least in part, of glass or of a material other than glass, such as atleast one thermoplastic material, for example at least one thermoplasticmaterial chosen from polypropylene and polyethylene, or a metal.

[0279] In a closed position of the container, the cap may be linked tothe container by a threading arrangement.

[0280] As an alternative, the cap may linked to the container by anarrangement other than a threading arrangement, such as snap-fitting.

[0281] In one embodiment, the product comprises an applicator elementwhich can be in the form of a brush having at least one tuft ofbristles. As an alternative, the applicator element may be in a formother than a brush having at least one tuft of bristles, for example, inthe form of a spatula or a foam pad.

What is claimed is:
 1. A nail varnish composition comprising, in acosmetically acceptable medium comprising at least one organic solvent,at least one block polymer, the composition being capable of forming afilm with a dampening power (tgδ) of greater than or equal to 0.4 at atemperature of 30° C. and a frequency of 20 Hz.
 2. The compositionaccording to claim 1, wherein the dampening power of the film is greaterthan or equal to 0.5.
 3. The composition according to claim 1, whereinthe film of the composition has a storage modulus E′ of greater than orequal to 1 MPa, at a temperature of 30° C. and a frequency of 0.1 Hz. 4.The composition according to claim 3, wherein the storage modulus E′ ofthe film is greater than or equal to 5 MPa.
 5. The composition accordingto claim 4, wherein the storage modulus E′ of the film is greater thanor equal to 10 Mpa.
 6. The composition according to claim 1, wherein thefilm of the composition has a breaking strain δr of greater than orequal to 5%, and/or a breaking energy per unit volume Wr of greater thanor equal to 0.2 J/cm³ at a temperature of 20° C.
 7. The compositionaccording to claim 6, wherein the film has a breaking strain δr rangingfrom 5% to 500% and/or a breaking energy per unit volume Wr of greaterthan or equal to 0.2 J/cm³ at a temperature of 20° C.
 8. The compositionaccording to claim 7, wherein the film has a breaking strain δr greaterthan or equal to 15% and/or a breaking energy per unit volume Wr ofgreater than or equal to 0.2 J/cm³ at a temperature of 20° C.
 9. Thecomposition according to claim 8, wherein the film has a breaking strainδr ranging from 15% to 400% and/or a breaking energy per unit volume Wrof greater than or equal to 0.2 J/cm³ at a temperature of 20° C.
 10. Thecomposition according to claim 1, wherein the at least one block polymercomprises at least a first block and at least a second block that havedifferent glass transition temperatures (Tg), wherein the at least onefirst and second blocks are linked together via at least oneintermediate segment comprising at least one constituent monomer of theat least one first block and at least one constituent monomer of the atleast one second block.
 11. The composition according to claim 10,wherein said at least one first block and said at least one second blockare incompatible with each other.
 12. The composition according to claim10, wherein the at least one first block is chosen from: a) a block witha Tg of greater than or equal to 40° C., b) a block with a Tg of lessthan or equal to 20° C., c) a block with a Tg of between 20 and 40° C.,and wherein the at least one second block is chosen from a block ofcategory a), b) or c) that is different from the at least one firstblock.
 13. The composition according to claim 12, wherein the block witha Tg of greater than or equal to 40° C. is totally or partially derivedfrom at least one monomer wherein a homopolymer prepared from the atleast one monomer has a Tg of greater than or equal to 40° C.
 14. Thecomposition according to claim 13, wherein the at least one monomer ischosen from: methacrylates of formula CH₂═C(CH₃)—COOR₁ wherein R₁ ischosen from linear and branched unsubstituted alkyl groups comprisingfrom 1 to 4 carbon atoms, and from a C₄ to C₁₂ cycloalkyl group,acrylates of formula CH₂═CH—COOR₂ wherein R₂ is chosen from a C₄ to C₁₂cycloalkyl group, and (meth)acrylamides of formula:

wherein R₇ and R₈, which may be identical or different, each are chosenfrom a hydrogen atom, and linear or branched alkyl groups comprising 1to 12 carbon atoms; or R₇ is H and R₈ is a 1,1-dimethyl-3-oxobutylgroup, and R′ is chosen from H and methyl.
 15. The composition accordingto claim 14, wherein the unsubstituted alkyl group of R₁ is chosen froma methyl, an ethyl, a propyl, and an isobutyl group.
 16. The compositionaccording to claim 14, wherein the C₄ to C₁₂ cycloalkyl group of R₂ ischosen from an isobornyl group and a tert-butyl group.
 17. Thecomposition according to claim 14, wherein the alkyl group with 1 to 12carbon atoms of R₇ and R₈ is chosen from an n-butyl, a t-butyl, anisopropyl, an isohexyl, an isooctyl, and an isononyl group.
 18. Thecomposition according to claim 13, wherein the at least one monomer ischosen from methyl methacrylate, isobutyl methacrylate, and isobornyl(meth)acrylate.
 19. The composition according to claim 12, wherein theblock with a Tg of less than or equal to 20° C. is totally or partiallyderived from at least one monomer wherein a homopolymer prepared fromthe at least one monomer has a Tg of less than or equal to 20° C. 20.The composition according to claim 19, wherein the at least one monomeris chosen from: acrylates of formula CH₂═CHCOOR₃, wherein R₃ is chosenfrom linear and branched C₁ to C₁₂ unsubstituted alkyl groups, with theexception of a tert-butyl group, wherein at least one heteroatom chosenfrom O, N and S is optionally intercalated; methacrylates of formulaCH₂═C(CH₃)—COOR₄, wherein R₄ is chosen from linear and branched C₆ toC₁₂ unsubstituted alkyl groups, wherein at least one heteroatom chosenfrom O, N and S is optionally intercalated; vinyl esters of formulaR₅—CO—O—CH═CH₂ wherein R₅ is chosen from linear and branched C₄ to C₁₂alkyl groups; C₄ to C₁₂ alcohol and vinyl alcohol ethers; and N—(C₄ toC₁₂)alkyl acrylamides.
 21. The composition according to claim 20,wherein said N—(C₄ to C₁₂)alkyl acrylamide is N-octylacrylamide.
 22. Thecomposition according to claim 20, wherein the at least one monomer ischosen from alkyl acrylates whose alkyl chain contains from 1 to 10carbon atoms, with the exception of the tert-butyl group.
 23. Thecomposition according to claim 12, wherein the block with a Tg ofbetween 20 and 40° C. is totally or partially derived from at least onemonomer wherein a homopolymer prepared from the at least one monomer hasa Tg of between 20 and 40° C.
 24. The composition according to claim 23,wherein the block with a Tg of between 20 and 40° C. is totally orpartially derived from at least one monomer wherein the correspondinghomopolymer has a Tg of greater than or equal to 40° C. and from atleast one monomer wherein the corresponding homopolymer has a Tg of lessthan or equal to 20° C.
 25. The composition according to claim 23,wherein the block with a Tg of between 20 and 40° C. is totally orpartially derived from at least one monomer chosen from methylmethacrylate, isobornyl acrylate, isobornyl methacrylate, trifluoroethylmethacrylate, butyl acrylate, and 2-ethylhexyl acrylate.
 26. Thecomposition according to claim 1, wherein the at least one block polymercomprises at least one first block and at least one second block, the atleast one first block having a Tg of greater than or equal to 40° C.,and the at least one second block having a Tg of less than or equal to20° C., the at least one first and second blocks are linked together viaat least one intermediate segment comprising: at least one constituentmonomer of the at least one first block and at least one constituentmonomer of the at least one second block.
 27. The composition accordingto claim 26, wherein the at least one first block is totally orpartially derived from at least one monomer wherein a homopolymerprepared from the at least one monomer has a Tg of greater than or equalto 40° C.
 28. The composition according to claim 26, wherein the atleast one first block is a copolymer derived from at least one monomerwherein the homopolymer prepared from the at least one monomer has a Tgof greater than or equal to 40° C.
 29. The composition according toclaim 27, wherein the at least one monomer is chosen from: methacrylatesof formula CH₂═C(CH₃)—COOR₁ wherein R₁ is chosen from linear andbranched unsubstituted alkyl groups containing from 1 to 4 carbon atoms,and from a C₄ to C₁₂ cycloalkyl group, acrylates of formula CH₂═CH—COOR₂wherein R₂ is a C₄ to C₁₂ cycloalkyl group, and (meth)acrylamides offormula:

wherein R₇ and R₈, which may be identical or different, each are chosenfrom a hydrogen atom, linear and branched alkyl groups comprising 1 to12 carbon atoms; or R₇ is H and R₈ is a 1,1-dimethyl-3-oxobutyl group,and R′ is chosen from H and methyl.
 30. The composition according toclaim 29, wherein the unsubstituted alkyl group of R₁ is chosen from amethyl, an ethyl, a propyl, and an isobutyl group.
 31. The compositionaccording to claim 29, wherein the C₄ to C₁₂ cycloalkyl group of R₂ ischosen from an isobornyl group and a tert-butyl group.
 32. Thecomposition according to claim 29, wherein the alkyl group with 1 to 12carbon atoms of R₇ and R₈ is chosen from an n-butyl, a t-butyl, anisopropyl, an isohexyl, an isooctyl, and an isononyl group.
 33. Thecomposition according to claim 27, wherein the at least one monomer ischosen from methyl methacrylate, isobutyl methacrylate, and isobornyl(meth)acrylate.
 34. The composition according to claim 26, wherein theat least one first block is present in the at least one block polymer inan amount ranging from 20% to 90% by weight of the at least one blockpolymer.
 35. The composition according to claim 34, wherein at least onefirst block is present in the at least one block polymer in an amountranging from 30% to 80% by weight of the at least one block polymer. 36.The composition according to claim 35, wherein the at least one firstblock is present in the at least one block polymer in an amount rangingfrom 50% to 70% by weight of the polymer
 37. The composition accordingto claim 26, wherein the at least one second block is totally orpartially derived from at least one monomer wherein a homopolymerprepared from the at least one monomer has a Tg of less than or equal to20° C.
 38. The composition according to claim 26, wherein the at leastone second block is a homopolymer derived from at least one monomerwherein a homopolymer prepared from the at least one monomer has a Tg ofless than or equal to 20° C.
 39. The composition according to claim 37,wherein the at least one monomer is chosen from: acrylates of formulaCH₂═CHCOOR₃, wherein R₃ is chosen from linear and branched C₁ to C₁₂unsubstituted alkyl groups, with the exception of the tert-butyl group,wherein at least one heteroatom chosen from O, N and S is optionallyintercalated; methacrylates of formula CH₂═C(CH₃)—COOR₄, wherein R₄ ischosen from linear and branched C₆ to C₁₂ unsubstituted alkyl groups,wherein at least one heteroatom chosen from O, N and S is optionallyintercalated; vinyl esters of formula R₅—CO—O—CH═CH₂ wherein R₅ ischosen from linear and branched C₄ to C₁₂ alkyl groups; C₄ to C₁₂alcohol and vinyl alcohol ethers; and N—(C₄ to C₁₂)alkyl acrylamides.40. The composition according to claim 39, wherein the N—(C₄ toC₁₂)alkyl acrylamide is N-octylacrylamide.
 41. The composition accordingto claim 37, wherein the at least one monomer is chosen from alkylacrylates whose alkyl chain contains from 1 to 10 carbon atoms, with theexception of the tert-butyl group.
 42. The composition according toclaim 26, wherein the at least one second block is present in the atleast one block polymer in an amount ranging from 5% to 75% by weight ofthe at least one block polymer.
 43. The composition according to claim42, wherein the at least one second block is present in the at least oneblock polymer in an amount ranging from 15% to 50% by weight of the atleast one block polymer.
 44. The composition according to claim 43,wherein the at least one second block is present in the at least oneblock polymer in an amount ranging from 25% to 45% by weight of the atleast one block polymer.
 45. The composition according to claim 1,wherein the at least one block polymer comprises at least one firstblock and at least one second block, the at least one first block havinga Tg of between 20 and 40° C. and the at least one second block having aTg of less than or equal to 20° C. or a Tg of greater than or equal to40° C., wherein the at least one first and second blocks are linkedtogether via at least one intermediate segment comprising at least oneconstituent monomer of the at least one first block and at least oneconstituent monomer of the at least one second block.
 46. Thecomposition according to claim 45, wherein the at least one first blockis totally or partially derived from at least one monomer wherein ahomopolymer prepared from the at least one monomer has a Tg of between20 and 40° C.
 47. The composition according to claim 45, wherein the atleast one first block is a copolymer derived from at least one monomerwherein a corresponding homopolymer has a Tg of greater than or equal to40° C., and from at least one monomer wherein a correspondinghomopolymer has a Tg of less than or equal to 20° C.
 48. The compositionaccording to claim 45, wherein the at least one first block is derivedfrom at least one monomer chosen from methyl methacrylate, isobornylacrylate, isobornyl methacrylate, butyl acrylate, and 2-ethylhexylacrylate.
 49. The composition according to claim 45, wherein the atleast one first block of the at least one block polymer is present in anamount ranging from 10% to 85% by weight of the at least one blockpolymer.
 50. The composition according to claim 49, wherein the at leastone first block is present in the at least one block polymer in anamount ranging from 30% to 80% by weight of the at least one blockpolymer.
 51. The composition according to claim 50, wherein the at leastone first block is present in the at least one block polymer in anamount ranging from 50% to 70% by weight of the at least one blockpolymer.
 52. The composition according to claim 45, wherein the at leastone second block has a Tg of greater than or equal to 40° C. and istotally or partially derived from at least one monomer wherein ahomopolymer prepared from the at least one monomer has a Tg of greaterthan or equal to 40° C.
 53. The composition according to claim 45,wherein the at least one second block has a Tg of greater than or equalto 40° C. and is a homopolymer derived from at least one monomer whereina homopolymer prepared from the at least one monomer has a Tg of greaterthan or equal to 40° C.
 54. The composition according to claim 47,wherein the at least one monomer is chosen from: methacrylates offormula CH₂═C(CH₃)—COOR₁ wherein R₁ is chosen from linear and branchedunsubstituted alkyl groups containing from 1 to 4 carbon atoms, and froma C₄ to C₁₂ cycloalkyl group, acrylates of formula CH₂═CH—COOR₂ whereinR₂ is chosen from a C₄ to C₁₂ cycloalkyl group, and (meth)acrylamides offormula:

wherein R₇ and R₈, which may be identical or different, each are chosenfrom a hydrogen atom, linear and branched alkyl groups comprising 1 to12 carbon atoms; or R₇ is H and R₈ is a 1,1-dimethyl-3-oxobutyl group,and R′ is chosen from H and methyl.
 55. The composition according toclaim 54, wherein the unsubstituted alkyl group of R₁ is chosen from amethyl, an ethyl, a propyl, and an isobutyl group.
 56. The compositionaccording to claim 54, wherein the C₄ to C₁₂ cycloalkyl group of R₂ ischosen from an isobornyl group and a tert-butyl group.
 57. Thecomposition according to claim 54, wherein the alkyl group with 1 to 12carbon atoms of R₇ and R₈ is chosen from an n-butyl, t-butyl, isopropyl,isohexyl, isooctyl, and isononyl group.
 58. The composition according toclaim 47, wherein the at least one monomer is chosen from methylmethacrylate, isobutyl methacrylate, and isobornyl (meth)acrylate. 59.The composition according to claim 45, wherein the at least one secondblock is present in the at least one block polymer in an amount rangingfrom 10% to 85% by weight of the at least one block polymer.
 60. Thecomposition according to claim 59, wherein the at least one second blockis present in the at least one block polymer in an amount ranging from20% to 70% by weight of the at least one block polymer.
 61. Thecomposition according to claim 60, wherein the at least one second blockis present in the at least one block polymer in an amount ranging from30% to 70% by weight of the at least one block polymer.
 62. Thecomposition according to claim 45, wherein the at least one second blockhas a Tg of less than or equal to 20° C. and is totally or partiallyderived from at least one monomer wherein a homopolymer prepared fromthe at least one monomer has a Tg of less than or equal to 20° C. 63.The composition according to claim 45, wherein the at least one secondblock has a Tg of less than or equal to 20° C. and is a homopolymerderived from at least one monomer wherein a homopolymer prepared fromthe at least one monomer has a Tg of less than or equal to 20° C. 64.The composition according to claim 62, wherein the at least one monomeris chosen from: acrylates of formula CH₂═CHCOOR₃, wherein R₃ is chosenfrom linear and branched C₁ to C₁₂ unsubstituted alkyl groups, with theexception of the tert-butyl group, wherein at least one heteroatomchosen from O, N and S is optionally intercalated; methacrylates offormula CH₂═C(CH₃)—COOR₄, wherein R₄ is chosen from linear and branchedC₆ to C₁₂ unsubstituted alkyl groups, wherein at least one heteroatomchosen from O, N and S is optionally intercalated; vinyl esters offormula R₅—CO—O—CH═CH₂ wherein R₅ is chosen from linear and branched C₄to C₁₂ alkyl groups; C₄ to C₁₂ alcohol and vinyl alcohol ethers; andN—(C₄ to C₁₂)alkyl acrylamides.
 65. The composition according to claim64, wherein the N—(C₄ to C₁₂)alkyl acrylamide is N-octylacrylamide. 66.The composition according to claim 62, wherein the at least one monomeris chosen from alkyl acrylates whose alkyl chain contains from 1 to 10carbon atoms, with the exception of the tert-butyl group.
 67. Thecomposition according to claim 62, wherein the at least one second blockis present in the at least one block polymer in an amount ranging from20% to 90% by weight of the at least one block polymer.
 68. Thecomposition according to claim 67, wherein the at least one second blockis present in the at least one block polymer in an amount ranging from30% to 80% by weight of the at least one block polymer.
 69. Thecomposition according to claim 68, wherein the at least one second blockis present in the at least one block polymer in an amount ranging from50% to 70% by weight of the at least one block polymer.
 70. Thecomposition according to claim 10, wherein the at least one first blockand/or the at least one second block comprises at least one additionalmonomer.
 71. The composition according to claim 70, wherein the at leastone additional monomer is chosen from hydrophilic monomers andethylenically unsaturated monomers comprising at least one silicon atom.72. The composition according to claim 70, wherein the at least oneadditional monomer is chosen from: ethylenically unsaturated monomerscomprising at least one carboxylic or sulphonic acid function,methacrylates of formula CH₂═C(CH₃)—COOR₆ wherein R₆ is chosen fromlinear and branched alkyl groups containing from 1 to 4 carbon atoms,the alkyl group being substituted with at least one substituent chosenfrom hydroxyl groups and halogen atoms, methacrylates of formulaCH₂═C(CH₃)—COOR₉, wherein R₉ is chosen from linear and branched C₆ toC₁₂ alkyl groups wherein at least one heteroatom chosen from O, N and Sis optionally intercalated, the alkyl group being substituted with atleast one substituent chosen from hydroxyl groups and halogen atoms;acrylates of formula CH₂═CHCOOR₁₀, wherein R₁₀ is chosen from linear andbranched C₁ to C₁₂ alkyl groups substituted with at least onesubstituent chosen from hydroxyl groups and halogen atoms,—(C₁-C₁₂)alkyl-O-POE (polyoxyethylene) with repetition of theoxyethylene unit from 5 to 30 times, and a polyoxyethylenated groupcomprising from 5 to 30 ethylene oxide units, and ethylenicallyunsaturated monomers comprising at least one tertiary amine function.73. The composition according to claim 72, wherein the alkyl group of R₆containing from 1 to 4 carbon atoms is chosen from a methyl, ethyl,propyl, and isobutyl group.
 74. The composition according to claim 72,wherein at least one of R₆ and R₁₀ is chosen from 2-hydroxypropylmethacrylate, 2-hydroxyethyl methacrylate, and trifluoroethylmethacrylate.
 75. The composition according to claim 72, wherein thealkyl group of at least one of R₆, R₉, and R₁₀ is substituted withhalogen atoms chosen from chlorine, bromine, iodine, and fluorine. 76.The composition according to claim 72, wherein the (C₁-C₁₂)alkyl-O-POEof R₁₀ is methoxy-POE.
 77. The composition according to claim 70,wherein the at least one additional monomer is chosen from acrylic acid,methacrylic acid, and trifluoroethyl methacrylate.
 78. The compositionaccording to claim 70, wherein the at least one additional monomer ispresent in an amount ranging from 1% to 30% by weight relative to thetotal weight of the at least one first and/or second blocks of the atleast one block polymer.
 79. The composition according to claim 1,wherein each of the at least one first and second blocks comprises atleast one monomer chosen from acrylic acid, acrylic acid esters,methacrylic acid, and methacrylic acid esters.
 80. The compositionaccording to claim 1, wherein each of the at least one first and secondblocks is totally derived from at least one monomer chosen from acrylicacid, acrylic acid esters, methacrylic acid, and methacrylic acidesters.
 81. The composition according to claim 10, wherein thedifference between the Tg of the at least one first and second blocks isgreater than 10° C.
 82. The composition according to claim 81, whereinthe difference between the Tg of the at least one first and secondblocks is greater than 20° C.
 83. The composition according to claim 82,wherein the difference between the Tg of the at least one first andsecond blocks is greater than 30° C.
 84. The composition according toclaim 83, wherein the difference between the Tg of the at least onefirst and second blocks is greater than 40° C.
 85. The compositionaccording to claim 10, wherein the at least one intermediate segment hasa Tg between the Tgs of the at least one first and second blocks. 86.The composition according to claim 1, wherein the at least one blockpolymer has a polydispersity index I of greater than 2.0.
 87. Thecomposition according to claim 86, wherein the at least one blockpolymer has a polydispersity index of greater than or equal to 2.5. 88.The composition according to claim 87, wherein the at least one blockpolymer has a polydispersity index of greater than or equal to 2.8. 89.The composition according to claim 88, wherein the at least one blockpolymer has a polydispersity index ranging from 2.8 to
 6. 90. Thecomposition according to claim 1, wherein the at least one block polymeris a film-forming linear block ethylene polymer.
 91. The compositionaccording to claim 1, wherein the at least one block polymer has aweight-average mass (Mw) which is less than or equal to 300,000.
 92. Thecomposition according to claim 91, wherein the at least one blockpolymer has a weight-average mass (Mw) which ranges from 35,000 to200,000.
 93. The composition according to claim 92, wherein the at leastone block polymer has a weight-average mass (Mw) which ranges from45,000 to 150,000.
 94. The composition according to claim 1, wherein theat least one block polymer has a number-average mass (Mn) which is lessthan or equal to 70,000.
 95. The composition according to claim 94,wherein the at least one block polymer has a number-average mass (Mn)which ranges from 10,000 to 60,000.
 96. The composition according toclaim 95, wherein the at least one block polymer has a number-averagemass (Mn) which ranges from 12,000 to 50,000.
 97. The compositionaccording to claim 1, wherein the at least one block polymer is notsoluble to an active material content of at least 1% by weight in wateror in a mixture of water and of a linear or branched lower monoalcoholhaving from 2 to 5 carbon atoms, without pH modification, at roomtemperature (25° C.).
 98. The composition according to claim 1, whereinthe at least one block polymer is not an elastomer.
 99. The compositionaccording to claim 1, wherein the at least one block polymer is presentin an amount ranging from 0.1% to 60% by weight relative to the totalweight of the composition.
 100. The composition according to claim 99,wherein the at least one block polymer is present in an amount rangingfrom 0.5% to 50% by weight relative to the total weight of thecomposition.
 101. The composition according to claim 100, wherein the atleast one block polymer is present in an amount ranging from 1% to 40%by weight relative to the total weight of the composition.
 102. Thecomposition according to claim 1, wherein the at least one organicsolvent medium comprises an organic solvent chosen from: ketones thatare liquid at room temperature; alcohols that are liquid at roomtemperature; glycols that are liquid at room temperature; propyleneglycol ethers that are liquid at room temperature; cyclic ethers;short-chain esters containing from 3 to 8 carbon atoms in total; ethersthat are liquid at room temperature; alkanes that are liquid at roomtemperature; alkyl sulphoxides; aldehydes that are liquid at roomtemperature; heterocyclic compounds; and propylene carbonate or ethyl3-ethoxypropionate.
 103. The composition according to claim 102, whereinthe ketones that are liquid at room temperature are chosen from methylethyl ketone, methyl isobutyl ketone, diisobutyl ketone, isophorone,cyclohexanone, and acetone.
 104. The composition according to claim 102,wherein the alcohols that are liquid at room temperature are chosen fromethanol, isopropanol, diacetone alcohol, 2-butoxyethanol, andcyclohexanol.
 105. The composition according to claim 102, wherein theglycols that are liquid at room temperature are chosen from ethyleneglycol, propylene glycol, pentylene glycol, and glycerol.
 106. Thecomposition according to claim 102, wherein the propylene glycol ethersthat are liquid at room temperature are chosen from propylene glycolmonomethyl ether, propylene glycol monomethyl ether acetate, anddipropylene glycol mono-n-butyl ether.
 107. The composition according toclaim 102, wherein the cyclic ethers are chosen from γ-butyrolactones.108. The composition according to claim 102, wherein the short-chainesters containing from 3 to 8 carbon atoms in total are chosen fromethyl acetate, methyl acetate, propyl acetate, isopropyl acetate,n-butyl acetate, isopentyl acetate, methoxypropyl acetate, and butyllactate.
 109. The composition according to claim 102, wherein the ethersthat are liquid at room temperature are chosen from diethyl ether,dimethyl ether, and dichlorodiethyl ether.
 110. The compositionaccording to claim 102, wherein the alkanes that are liquid at roomtemperature are chosen from decane, heptane, dodecane, and cyclohexane.111. The composition according to claim 102, wherein the alkylsulphoxides are dimethyl sulphoxides.
 112. The composition according toclaim 102, wherein the aldehydes that are liquid at room temperature arechosen from benzaldehyde and acetaldehyde.
 113. The compositionaccording to claim 102, wherein the heterocyclic compounds aretetrahydrofurans.
 114. The composition according to claim 1, wherein theat least one organic solvent medium has a polarity P ranging from 0.422to 0.725.
 115. The composition according to claim 1, wherein the atleast one organic solvent medium is present in an amount ranging from10% to 95% by weight relative to the total weight of the composition.116. The composition according to claim 115, wherein the at least oneorganic solvent medium is present in an amount ranging from 15% to 80%by weight relative to the total weight of the composition.
 117. Thecomposition according to claim 116, wherein the at least one organicsolvent medium is present in an amount ranging from 20% to 60% by weightrelative to the total weight of the composition.
 118. The compositionaccording to claim 1, further comprising at least one additionalfilm-forming polymer.
 119. The composition according to claim 118,wherein the at least one additional film-forming polymer is present inan amount ranging from 0.1% to 60% by weight relative to the totalweight of the composition.
 120. The composition according to claim 119,wherein the at least one additional film-forming polymer is present inan amount ranging from 2% to 40% by weight relative to the total weightof the composition.
 121. The composition according to claim 120, whereinthe at least one additional film-forming polymer is present in an amountranging from 5% to 25% by weight relative to the total weight of thecomposition.
 122. The composition according to claim 1, furthercomprising at least one plasticizer present in an amount of less than20% by weight relative to the total weight of the composition.
 123. Thecomposition according to claim 122, wherein the at least one plasticizeris present in an amount of less than 15% by weight relative to the totalweight of the composition.
 124. The composition according to claim 123,wherein the at least one plasticizer is present in an amount of lessthan 10% by weight relative to the total weight of the composition. 125.The composition according to claim 124, wherein the at least oneplasticizer is present in an amount of less than 5% by weight relativeto the total weight of the composition.
 126. The composition accordingto claim 1, further comprising at least one dyestuff.
 127. Thecomposition according to claim 126, wherein the at least one dyestuff ispresent in an amount ranging from 0.01% to 50% by weight relative to thetotal weight of the composition.
 128. The composition according to claim127, wherein the at least one dyestuff is present in an amount rangingfrom 0.01% to 30% by weight relative to the total weight of thecomposition.
 129. A non-therapeutic cosmetic makeup or care process fornails, the process comprising applying to the nails one coat of a nailvarnish composition comprising, in a cosmetically acceptable medium, atleast one block polymer, the composition being capable of forming a filmwith a dampening power (tgδ) of greater than or equal to 0.4 at atemperature of 30° C. and a frequency of 20 Hz.
 130. A method forproducing a glossy film comprising applying to nails a nail varnishcomposition comprising, in a cosmetically acceptable medium, at leastone block polymer, the composition being capable of forming a film witha dampening power (tgδ) of greater than or equal to 0.4 at a temperatureof 30° C. and a frequency of 20 Hz, wherein a film is produced on thenails and the film has at least one of good staying power and good wearresistance.
 131. A nail varnish product comprising: i) a containerdelimiting at least one compartment closed by a cap, and ii) acomposition received inside said compartment, said compositioncomprising, in a cosmetically acceptable medium comprising at least oneorganic solvent, at least one block polymer, the composition beingcapable of forming a film with a dampening power (tgδ) of greater thanor equal to 0.4 at a temperature of 30° C. and a frequency of 20 Hz.132. A nail varnish product according to claim 131 wherein the containeris, at least in part, formed of glass.
 133. A nail varnish productaccording to claim 131 wherein the container is, at least in part,formed of a material other than a glass.
 134. A nail varnish productaccording to claim 133, wherein said material other than glass is chosenfrom thermoplastic materials and from metals.
 135. A nail varnishproduct according to claim 134, wherein said thermoplastic materials arechosen from polypropylene and polyethylene.
 136. A nail varnish productaccording to claim 131, wherein in a closed position of the container,the cap is linked to the container by a threading arrangement.
 137. Anail varnish product according to claim 131, wherein in a closedposition of the container, the cap is linked to the container by anarrangement other than a threading arrangement, such as snap-fitting.138. A nail varnish product according to claim 131, wherein it comprisesan applicator element in the form of a brush having at least one tuft ofbristles.
 139. A nail varnish product according to claim 131, wherein itcomprises an applicator element in a form other than a brush having atleast one tuft of bristles.
 140. A nail varnish composition according toclaim 139, wherein said applicator element is in the form of a spatulaor a foam pad.